Method of making a slip ring unit



April 5, 1969 F. E. BUSCHBOM 3,438,123

METHOD OF MAKING A SLIP RING UNIT Filed Oct. 22, 1965 Sheet of 2 FIG. 1

FIE: E

6 J3 FIE: 5 7 65 48 60 62 6/ 4.8

1 N VENTOR.

FIG. 4 5 Basra/aw z/rro 24ers April 15, 1969 F. E. BUSCHBOM METHOD OF MAKING A SLIP RING UNIT Sheet Z of 2 Filed Oct. 22, 1965 drramvlys United States Patent 3,438,123 METHOD OF MAKING A SLIP RING UNIT Floyd E. Buschborn, Long Lake, Minn., assignor to Van Dale Corporation, Wayzata, Minn., a corporation of Minnesota Filed Oct. 22, 1965, Ser. No. 501,159 Int. Cl. H01r 43/00; B23p 17/00 US. Cl. 29-597 8 Claims This invention relates to an electrical connection and a method of making an electrical connection. More particularly, the invention is directed to an electric contact ring assembly having a slip ring unit cooperating with a brush unit to make an electrical connection.

As disclosed in Patents 2,794,560 and 3,181,715, a group of top traversing silo unloaders have electric contact ring assemblies or transition assemblies for transferring current from a stationary portion of the machine to a portion of the machine rotatable about a vertical axis for collecting silage and delivering silage to the stationary portion. These contact ring assemblies have slip ring units which are expensive to manufacture as they require many separate fabricating operations as well as Waste a considerable amount of conductive material, as cooper. When the annular metal conductive rings and the non-conductive ring support of the slip ring unit are combined by molding the support about the rings the unequal co-efficients of thermo expansion and contraction of the metal rings and the synthetic resinous support cause the rings to warp on cooling as well as separate portions of the rings from the support. Portions of the support are placed under stress making the support susceptible to breakage in use.

It is the object of this invention to provide an improved electric ring contact assembly for a silo unloader which has economy in construction, minimizes labor and waste material in fabrication and is sturdy and reliable in use.

A further object of the invention is to provide an improved method of fabricating a slip ring unit of an electric contact ring assembly.

Another object of the invention is to provide a slip ring unit having a plurality of annular conductor rings which can be assembled and disassembled in a minimum of time and labor on a support of non-conductive material.

In the drawing:

FIGURE 1 is a sectional view of the electric contact ring assembly of this invention on a silo unloader;

FIGURE 2 is an enlarged sectional of a fragmentary portion of the conductor slip ring unit of the electric contact ring assembly of FIGURE 1;

FIGURE 3 is an enlarged sectional View of another fragmentary portion of the conductor slip ring unit of the electric contact ring assembly of FIGURE 1;

FIGURE 4 is a fragmentary perspective view of the metal conductor ring casting;

FIGURE 5 is a plan view of the bottom of the metal conductor ring casting;

FIGURE 6 is a plan view of the conductor slip ring support; and

FIGURE 7 is an enlarged sectional view taken along the line 7--7 of FIGURE 6.

Referring to the drawing, there is shown in FIGURE 1, the electrical contact ring assembly or transition assembly of this invention indicated generally at 10 for a silo unloader such as the silo unloader in Patent 2,794,560. The electric contact ring assembly 10 comprises a stationary sub-assembly 11 positioned above a rotatable sub-assembly 12 connected to the stationary sub-assembly 11 for rotation about a generally upright axis. Sub-assembly 11 comprises an upright tubular member 13 having an upright Venturi shaped passage 14 for directing material into a chute 16 projected upwardly and outwardly toice ward the silo wall. Chute 16 is pivotally mounted to the top of the tubular member 13 by a pair of bolt and nut assemblies 17 one of which is shown. Integral with the mid-portion of the tubular member 13 is an annular outward radial flange 18 having a downwardly projected peripheral sidewall 19. A heavy annular member or ring 21 is secured to the lower end of the sidewall 19. Radial flange 18 and sidewall 19 define an annular chamber 22 accommodating a slip ring unit indicated generally at 23. Bolts 24 projected through suitable holes in circumferentially spaced ears 25 integral with the periphery of support 23 and threaded into bores in the flange 18 secure the slip ring unit 23 to the flange 18. When the slip ring unit 23 is mounted on flange 18 a portion of the slip ring unit projects through opening 26 into an enclosed junction box defined by an upright wall 27 on flange 18. The top of the upright wall 27 has an opening 28 covered by a flat closure 29.

Sub-assembly 12 has an upright tubular member 31 adapted to be secured to the discharge structure of a silo unloader impeller housing to receive material into upright passage 32 and direct the material to the upright passage 14 of the stationary sub-assembly 11. Tubular member 31 has an integral radial flange 33 having a circumferential end section riding on the top of annular ring 21. The lower end of tubular member 13 has a downwardly projected annular lip 34 extended into an annular recess in the top of the tubular member 31. An annular seal 36 interposed between the top of the flange 33 and the tubular member 13 prevents entrance of foreign material into the annular chamber 22. Grease fittings 37 are used to lubricate engaging surfaces of the sub-assemblies 11 and 12.

Flange 33 has an opening 38 accommodating a brush unit indicated generally at 39. Included in the brush unit 39 is a support 41 of non-conductive resinous material having upright bores for accommodating six spaced brushes 42 having flat upper ends in engagement with the slip ring unit 23. Springs 43 engage each of the brushes 42 and bias them in an upward direction. Projected downwardly from each brush 42 are conductor elements terminating in eyes 45 adapted to be connected to lines leading to an electric motor or the like, used to operate the silo unloader.

Slip ring unit 23 has three metal annular conductors or slip rings 44, 46 and 47. Each of the conductors are flat annular cast metal members cast from conductive metal material such as copper, copper alloys and the like. Slip rings 44, 46 and 47 are identical except for the difference in the diameters of the rings. Rings 44, 46 and 47 are mounted in concentric and spaced relative relation in an annular support 48 of non-conductive material such as a hard synthetic resinous material. Support 48 has three annular and concentric recesses or channels 49, 51 and 52 defined by concentric annular walls 53 and 54 and inner and outer annular walls 55 and 56 concentric with the walls 53 and 54.

Referring to FIGURE 3, there is shown an enlarged portion of support 48 in assembled relation with the slip rings 44, 46 and 47. The base of each of the recesses 49, 51 and 52 has an annular groove 57 receiving a rectangular lug 58 integral with the top side of the slip ring 46. The lug 58 has a threaded bore 59 receiving a screw 60 projected through a suitable hole in the flat base of the support 48. The head of the screw 60 is located in a recess 61 and covered with a non-conductive material 62.

As shown in FIGURE 4, each slip ring 44, 46 and 47 has two circu mferentially spaced rectangular lugs 58A and 58B identical with the lug 58 for receiving screws to secure the rings to support 48. Circumferentially spaced between each of the lugs 58, 58A and 583 on each ring I are upwardly projected tapered bosses 63, 63A and 63B. As shown in FIGURE 2, boss 63 is cast integral with slip ring 46 and tapers inwardly in an upward direction. Boss 63 projects through a tapered opening 64 in a collar 65 integral with the base 48. A threaded bore 66 extends axially into boss 63 and accommodates a bolt 67 used to secure electrical conductor 68 to the boss 63. The top of the boss 63 is flush with the top of collar 65. A copper washer 70 is secured to the top of boss 63 with bolt 67. The lower side of slip ring 46 has a flat smooth and con tinuous face 69 engageable with the flat end of the middle two brushes 42 to provide an electrical contact between slip ring 46 and middle two brushes 42 whereby electric power may be transmitted through the conductor 68, the slip ring 46, the middle two brushes 42, and to the electric motor driving the silo unloader. Rings 44 and 47 are positioned in recesses 49 and 52 and secured to support 48 in the same manner as ring 46. Bosses 63A and 63B project through collars 65A and 65B respectively on support 48.

In the method of fabrication of the ring unit 23 the annular slip rings 44, 46 and 47 are initially cast of electrically conductive metal in three concentric spaced rings as shown in FIGURE 4 and indicated generally by single casting 71. Casting 7.1 is made in a single casting operation of electrically conductive metal, such as copper, copper alloys and the like. The rings are substantially flat annular members connected with a plurality of circumferentially spaced flat runners or gates 72 and 73. The tapered boss 63 is integral with and projects upwardly from the top of the ring 46. In the same manner tapered bosses 63A and 63B project upwardly from the annular slip rings 44 and 47, respectively. Circumferentially spaced from the bosses 63, 63A and 63B are upwardly projected lugs 58, 58A and 58B. The lugs are rectangularly shaped and have a width narrower than the width of the associated slip ring. As shown in FIG. 5, each slip ring has a flat continuous face 69, 69A and 69B on the) side opposite the bosses and lugs. Rings 44, 46 and 47 as a single casting are pressed flat with rollers into a single plane. The faces 69, 69A and 69B are machined into smooth continuous surfaces. The machining of the slip ring is completed by providing bosses 63, 63A and 63B as well as lugs 58, 58A and 58B with threaded axial bores 66 and 59, respectively. After the machining operations are completed the rings 44, 46 and 47 are separated from each other by removing all the gates 72 and 73.

Referring to FIGURES 6 and 7, the support 48 is a one-piece annular member molded from synthetic resinous non-electrical conductive material. The lower side of the support 48 has three concentric recesses or grooves 49, 51 and 52 separated by concentrically disposed circular walls 53, 54, 55 and 56. The tapered bores of each of the cylindrical projections or collars 65, 65A and 65B open to the base of the grooves. The inside collar 65A is longer than collars 65 and 65B. As shown in FIGURE 6, collar 65 is circumferentially spaced from collars 65A and 65B. Circumferentially spaced from collars 65, 65A and 65B and open to the grooves are holes 74 for accommodating the screws 60 used to secure the slip rings to support 48.

The slip rings 44, 46 and 47 are assembled on support 48 by placing the slip ring 44 in the groove 49 with the tapered boss 63A projected through the cylindrical projection 65A. This aligns holes 74 with threaded bores in the rectangular lugs 58A. Screws similar to screw 60 are used to secure the ring 44 to the support 48. The heads of the screws are located in recesses which are filled with a non-conductive material. In a similar manner rings 46 and 47 are mounted in the support 48 and secured thereto with screws 60. The machined smooth.- flat surfaces 69, 69A and 69B of each of the conductor rings are located along the base sections of the grooves 49, 51 and 52 providing three concentrically spaced continuous electrical conductors.

As shown in FIGURE 1, the ring unit 23 is positioned in the annular chamber 22 and secured to the stationary flange 18 by bolts 24 projected through the holes in the support cars 25. With the ring 21 removed the stationary sub-assembly 25 is then placed over the flange 33 of the movable sub-assembly 12. Ring 21 is then secured to the end of the sidewall 19 to couple the stationary sub-assembly 11 to the rotatable sub-assembly 12. Brush unit 39 is then inserted through the opening 38 in the flange 33 with the brushes 42 projected into the annular recesses 49, 51 and 52 engaging the flat continuous surfaces of the slip rings 44, 46 and 47, respectively.

In use, electricity is transmitted from any suitable source of electric current by a power line or cable into the junction box 27 and by leads to the terminals 67, 67A and 67B on the upper ends of bosses 63, 63A and 63B. Electric current is then transferred through the bosses to the annular slip rings 44, 46 and 47. Brushes 42 maintained in communication with the slip rings by the springs 43 pick up the electric current which is transferred via a cable to an electric motor mounted on the rotating part of the silo unloader. As sub-assembly 12 of the silo unloader rotates it moves brushes 42 around the slip rings 44, 46 and 47 which are held stationary with the subassembly 11. The silo unloader will convey and move ensilage upwardly through the passages 32 and 14 and outwardly through the chute 16 as shown by arrows in FIGURE 1.

The specific embodiment described is given by way of example. The invention is limited only by the terms of the appended claims.

The embodiments of the invention in which an exclusive property and privilege is claimed are defined as follows:

1. A method of making a slip ring unit comprising the steps of: casting electrically conductive metal into three concentrically spaced rings in a single unit with the rings connected with a plurality of circumferentially spaced runners, each ring having a continuous substantially flat face, the side of the ring opposite the flat face having circumferentially spaced lugs and a boss, flattening the ring unit into a single plane, machining the flat face of each ring into a smooth continuous surface, providing threaded bores in the lugs and bosses of each ring, separating the rings from each other by removing the runners, forming from non-conductive material a support having three concentric circular channels for accommodating said three rings, said support having bores open to each channel and a groove in the base of each channel, locating the rings in the channels with the lugs in the grooves and the bosses in the bores, and securing the rings to the support with bolts extended through the support and threaded into the threaded bores in the lugs.

2. The method of making a slip ring unit defined in claim 1 including the step of covering the bolts used to secure the rings to the support with non-conductive material.

3. The method of making a slip ring unit defined in claim 1 wherein the rings are cast with tapered bosses and the support is formed with tapered bores to accommodate the bosses.

4. A method of making a slip ring unit comprising the steps of: casting electrically conductive metal into a flat annular ring having a continuous substantially flat face and at least one lug and at least one boss projected from the side opposite the flat face, flattening the ring into a substantially singular plane, machining the flat face into a smooth continuous surface, providing a threaded bore in the lug, forming from non-conductive material a support having a concentric circular channel of a size and diameter to accommodate said ring, said support having a bore open to the channel and a groove in the base of the channel, locating the ring in the channel with the lug in the groove and the boss in the bore, and securing the ring to the support with fastening means extended through said support and into the threaded bore in said lug.

5. The method of making a slip ring defined in claim 4 wherein the ring is cast with a tapered boss and the support is formed with a tapered bore to accommodate the boss.

6. A method of making a slip ring unit comprising the steps of: casting electrically conductive metal into a flat annular ring having a continuous substantially fiat face and at least one boss projected from the side opposite the fiat face, flattening the ring into a substantially singular plane, making the flat face into a smooth continuous surface, forming from non-conductive material support having a concentric circular channel of a size and diameter to accommodate said ring, said support having a bore open to the channel, locating the ring in the channel with the boss in the bore, and securing the ring to the support with fastening means extended through said support and attached to said ring.

7. A method of making a slip ring unit comprising the steps of: casting electrically conductive metal into a plurality of concentrically spaced rings in a single unit with the rings connected with a plurality of runners, each ring having a continuously substantially flat face, the side of the ring opposite the flat face having a boss, making the flat face of each ring into a smooth continuous surface, separating the rings from each other by removing the runners, forming from non-conductive material a sup- References Cited UNITED STATES PATENTS 3,314,038 4/1967 Rutten 339-5 3,181,715 5/1965 Olson 339-5 3,066,386 12/1962 Filipczak 29-597 3,017,595 1/ 1962 Drollinger et al. 3398 2,898,572 8/1959 Shinn 339-8 JOHN F. CAMPBELL, Primary Examiner. RICHARD B. LAZARUS, Assistant Examiner.

U.S. Cl. X.R. 339-8; 29-629 

1. A METHOD OF MAKING A SLIP RING UNIT COMPRISING THE STEPS OF: CASTING ELECTRICALLY CONDUCTIVE METAL INTO THREE CONCENTRICALLY SPACED RINGS IN A SINGLE UNIT WITH THE RINGS CONNECTED WITH A PLURALITY OF CIRCUMFERENTIALLY SPACED RUNNERS, EACH RING HAVING A CONTINUOUS SUBSTANTIALLY FLAT FACE, THE SIDE OF THE RING OPPOSITE THAT FLAT FACE HAVING CIRCOMFERENTIALLY SPACED LUGS AND A BOSS, FLATTENING THE RING UNIT INTO A SINGLE PLANE, MACHINING THE FLAT FACE OF EACH RING INTO A SMOOTH CONTINUOUS SURFACE, PROVIDING THREADED BORES IN THE LUGS AND BOSSES OF EACH RING, SEPARATING THE RINGS FROM EACH OTHER BY REMOVING THE RUNNERS, FORMING FROM NON-CONDUCTIVE MATERIAL A SUPPORT HAVING THREE CONCENTRIC CIRCULAR CHANNELS FOR ACCOMODATING SAID THREE RINGS, SAID SUPPORT HAVING BORES OPEN TO EACH CHANNEL AND A GROOVE IN THE BASE OF EACH CHANNEL, LOCATING THE RINGS IN THE CHANNELS WITH THE LUGS IN THE GROOVES AND THE BOSSES IN THE BORES, AND SECURING THE RINGS TO THE SUPPORT WITH BOLTS EXTENDED THROUGH THE SUPPORT AND THREADED INTO THE THREADED BORES IN THE LUGS. 